1. Field of the Disclosure
This disclosure relates generally to apparatus and method for completing wellbores that utilize one or more shape conformable devices or members, including, but not limited to, packers, sand screens and inflow control devices.
2. Background of the Art
Wellbores are drilled in subsurface formations for the production of hydrocarbons (oil and gas). Wells often extend to depths of more than 15,000 feet. Many such wellbores are deviated or horizontal. After a wellbore is formed, a production string is installed therein for efficient production of the hydrocarbons from subsurface formations. The production string may be installed in an open hole or a cased hole and it typically includes a tubing that extends from the surface to the wellbore depth. A variety of devices are placed inside and around the tubing for efficient production of hydrocarbons from the subsurface formations. Some of these devices may utilize materials or members that expand when heated. Such materials are generally referred to herein as “conformable materials” and the devices that utilize such materials as conformable devices. Such devices are installed on the production string in their unexpanded or compressed state or form and they expand to their intended downhole form when heated in the wellbore by fluid in the wellbore or by artificial means. Such devices include, but are not limited to, packers, sand screens, seals and certain flow control devices. Shape memory materials or swellable materials are utilized as conformable or expandable materials in devices for use in wellbore (“downhole devices”). A shape memory material has a glass transition temperature and when such a material is heated to or above such temperature, it expands, and can then be shaped into a desired expanded shape. The shape memory member may then be compressed to a desired compressed shape or state from its desired expanded shape while the temperature is at or above its glass transition temperature. If the temperature is reduced below the glass transition temperature while the member is in the compressed shape, it will retain remain in the compressed state until heated to or above its glass transition temperature. The member will expand to its desired expanded state after it remains heated for a certain time period. A swellable material expands when exposed to a heated fluid, such as oil and/or water.
A device or a member utilizing such a shape memory material may be placed or deployed in a wellbore in its initial shape. If the temperature of such a member increases to or above its glass transition temperature for a sufficient time period, it will expand to its original expanded shape. The required heat may be provided by any suitable method or mechanism. Typically, shape memory materials are heated in the wellbore by supplying a heated fluid. However, when the supply of the heated fluid is stopped, the shape memory material temperature falls to the temperature of the wellbore, which typically is below its glass transition temperature and thus ceases the expand.
Deployment rates of conformable devices can vary with the increase in temperature. Therefore, it is beneficial if the conformable devices or members retain their temperature above the onset deployment temperature of the conformable materials in the downhole environment for a period of time after the external heat supply has been stopped to ensure that the conformable device has expanded to its desire expanded shape.
The disclosure herein provides materials that contain a shape memory material and heat transfer nanoparticles that store thermal energy when external heat energy is supplied to such materials and transfer such stored heat energy to the shape memory material after the external heat energy supply has been stopped and devise that utilize such materials.